Scroll compressor with recesses and protrusions

ABSTRACT

A compressor is provided. The compressor may include a fixed wrap, and an orbiting scroll having an orbiting wrap engaged with the fixed wrap to form compression chambers. The fixed wrap and the orbiting wrap may have irregular wrap curves. At least one interference avoiding portion at which a spacing between the wraps is greater than an orbiting radius or at least one gap compensating portion at which the spacing between the wraps is smaller than the orbiting radius, in a state in which a center of the fixed scroll and a center of the orbiting scroll are aligned with each other, may be provided on a sidewall surface of the fixed wrap or the orbiting wrap, whereby frictional loss or abrasion due to interference between the wraps or a refrigerant leakage due to a gap between the wraps may be prevented.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.17/750,740, filed May 23, 2022, which is a Continuation of U.S. patentapplication Ser. No. 15/956,970, filed Apr. 19, 2018, which is aContinuation of U.S. patent application Ser. No. 14/708,436, filed May11, 2015 (now U.S. Pat. No. 9,951,773), which claims priority under 35U.S.C. § 119 to Korean Application No. 10-2014-0107929, filed on Aug.19, 2014, whose entire disclosures are hereby incorporated by reference.

BACKGROUND 1. Field

A scroll compressor is disclosed herein.

2. Background

In general, scroll compressors are widely used for refrigerantcompression in air-conditioners, to obtain a relatively highercompression ratio in comparison to other types of compressors, andacquire a stable torque resulting from smooth strokes of suction,compression, and discharge of the refrigerant. A behavior of the scrollcompressor is dependent on shapes of a fixed wrap and an orbiting wrap.The fixed wrap and the orbiting wrap may have a random shape, buttypically they have a shape of an involute curve, which is easy tomanufacture. An involute curve refers to a curve corresponding to atrack drawn by an end of a thread when unwinding the thread wound arounda basic circle with a predetermined radius. When such an involute curveis used, the wrap has a uniform thickness, and a rate of volume changeof the compression chamber is constantly maintained. Hence, a number ofturns of the wrap should be increased to obtain a sufficient compressionratio, which may, however, cause the compressor to be increased in sizecorresponding to the increased number of turns of the wrap.

The scroll compressor may be provided with a rotation-preventing member,such as an Oldham ring, provided between the orbiting scroll and a framethat supports the orbiting scroll or a fixed scroll, so as to induce anorbiting motion by preventing rotation of the orbiting scroll. However,when the Oldham ring is provided in the scroll compressor, a gap isformed between a key and a key groove, which are located at or on theOldham ring and the orbiting scroll, respectively. The gap may cause theorbiting scroll to be temporarily rotated or inversely rotated duringoperation. Due to the rotation or inverse rotation of the orbitingscroll, an interference or gap may be formed between an orbiting wrapand a fixed wrap according to a crank angle in each of a compressionchamber (hereinafter, referred to as “a first compression chamber”)formed outside of the orbiting wrap, and a compression chamber(hereinafter, referred to as a “second compression chamber”) formedinside of the orbiting wrap. This results from the fact that an orbitingradius of the orbiting wrap changes without remaining still at a momentof the rotation or the inverse rotation of the orbiting scroll. When thefixed wrap and the orbiting wrap have an involute or algebraic spiralshape, in which a wrap curve of the fixed wrap and the orbiting wrap hasa uniform shape along a turning direction of the wrap, the interferenceor gap is minorly generated. However, in a scroll compressor in whichthe wrap curve of the fixed wrap and the orbiting wrap is irregular inthe turning direction of the wrap, a great interference or gap may begenerated. In this manner, if such interference or gap is generated at aspecific portion between the orbiting wrap of the orbiting scroll andthe fixed wrap of the fixed scroll, abrasion due to interference betweenthe wraps or compression loss due to the gap between the wraps may becaused.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be described in detail with reference to the followingdrawings in which like reference numerals refer to like elements, andwherein:

FIG. 1 is a longitudinal sectional view of a bottom compression typescroll compressor according to an embodiment;

FIG. 2 is an enlarged longitudinal sectional view of a compressiondevice of the bottom compression type scroll compressor of FIG. 1 ;

FIG. 3 is a planar view illustrating a coupled state of an Oldham ringto an orbiting scroll in the bottom compression type scroll compressorillustrated in FIG. 1 ;

FIG. 4 is a planar view of a fixed wrap and an orbiting wrap each havingan irregular wrap curve according to an embodiment;

FIG. 5 is a graph illustrating interpretation of an orbiting radiusdisplacement of a gap section with respect to A-path of FIG. 4 ;

FIG. 6 is a graph illustrating interpretation of an orbiting radiusdisplacement in a gap section with respect to B-path of FIG. 4 ; and

FIG. 7 is a planar view of the B-path as a representative example forillustrating a structure for avoiding interference and a gap between afixed wrap and an orbiting wrap forming the A-path and the B-path.

DETAILED DESCRIPTION

Hereinafter, description will be given in detail of a scroll compressoraccording to an embodiment with reference to the accompanying drawings.Where possible, like reference numerals have been used to indicate likeelements, and repetitive disclosure has been omitted.

FIG. 1 is a longitudinal sectional view of a bottom compression typescroll compressor according to an embodiment. FIG. 2 is an enlargedlongitudinal sectional view of a compression device of the bottomcompression type scroll compressor of FIG. 1 .

The bottom compression type scroll compressor according to an embodimentmay include a casing 1, a motor 2 provided within an inner space 1 a ofthe casing 1 to generate a rotational force, and a compression device 3provided below the motor 2 to compress a refrigerant by receiving therotational force transferred from the motor 2. The casing 1 may includea cylindrical shell 11 that forms a hermetic container, an upper shell12 that covers a top of the cylindrical shell 11 to form the hermeticcontainer, and a lower shell 13 that covers a bottom of the cylindricalshell 11 to form the hermetic container and simultaneously form an oilstorage space 1 b.

A refrigerant suction pipe 15 may penetrate through a side surface ofthe cylindrical shell 11 to communicate directly with a suction chamberof the compression device 3, and a refrigerant discharge pipe 16 thatcommunicates with the inner space 1 a of the casing 1 may be provided ata top of the upper shell 12. The refrigerant suction pipe 16 maycorrespond to a path along which a compressed refrigerant, which may bedischarged from the compression device 3 into the inner space 1 a of thecasing 1, may be discharged to the outside. An oil separator (notillustrated), in which oil mixed with the discharged refrigerant may beseparated from the refrigerant, may be connected to the refrigerantdischarge pipe 16.

A stator 21 that forms the motor 2 may be fixed to an upper portion ofthe casing 1. A rotor 22 that forms the motor 2 together with the stator21 and is rotated by interaction with the stator 21 may be rotatablyprovided within the stator 21.

The stator 21 may be provided with a plurality of slots (no referencenumeral) formed on an inner circumferential surface thereof along acircumferential direction. A coil 25 may be wound around each of theplurality of slots. A passage 26 may be formed, for example, by cuttingan outer circumferential surface of the stator 21 into a D-cut shape,such that a refrigerant or oil may flow between the outercircumferential surface of the stator 21 and an inner circumferentialsurface of the cylindrical shell 11.

A main frame 31 that forms the compression device 3 may be providedbelow the stator 21 with a predetermined gap therebetween, and fixed toa lower side of the casing 1. A fixed scroll 32 (hereinafter, alsoreferred to as a “first scroll”) may be fixed to a lower surface of themain frame 31 with an orbiting scroll 33 (hereinafter, also referred toas a “second scroll”), which may be eccentrically coupled to arotational shaft 5, which is discussed hereinbelow, interposedtherebetween. The orbiting scroll 33 may be installed between the mainframe 31 and the fixed scroll 32 to perform an orbiting motion. Theorbiting scroll 33 may form a plurality of compression chambers S1,which may include a suction chamber, an intermediate pressure chamber,and a discharge chamber, along with the fixed scroll 32 while performingthe orbiting motion. The fixed scroll 32 may be coupled to the mainframe 31 to be movable up and down.

The main frame 31 may have an outer circumferential surface, which maybe shrink-fitted or welded onto the inner circumferential surface of thecylindrical shell 11, for example. A first bearing hole 311 may beformed through a center of the main frame 31 in an axial direction. Amain bearing 51 of the rotational shaft 5, which may correspond to afirst bearing, may be rotatably inserted into the first bearing hole 311and be supported thereby. A back pressure chamber S2, which may form aspace along with the fixed scroll 32 and the orbiting scroll 33 so as tosupport the orbiting scroll 33 by pressure of the space, may be formedat a lower surface of the main frame 31.

The fixed scroll 32 may include a disk 321 formed in an approximatelycircular shape, and a fixed wrap 322, which may be formed on an uppersurface of the disk 321 and engaged with an orbiting wrap 332, which isdiscussed hereinbelow, so as to form the compression chambers S1. Asuction opening 323, which may be connected to the refrigerant suctionpipe 15, may be formed at one side of the fixed wrap 322. A dischargeopening 324, which may communicate with the discharge chamber, such thata compressed refrigerant may be discharged therethrough, may be formedthrough the disk 321.

The discharge opening 324 may be formed to extend toward the lower shell13, and a discharge cover 34 may be coupled to a lower surface of thefixed scroll 32 so as to store the discharged refrigerant and guide ittoward a refrigerant passage, which will be discussed hereinbelow. Thedischarge cover 34 may be coupled to the lower surface of the fixedscroll 32 in a sealing manner so as to separate a discharge passage (noreference numeral) of the refrigerant from the oil storage space 1 b.

The discharge cover 34 may have an inner space, in which both thedischarge opening 324 and an inlet of a refrigerant passage PG may beaccommodated. The refrigerant passage PG may be formed through the fixedscroll 32 and the main frame 31 so as to guide a refrigerant, which maybe discharged from the compression chambers S1 into the inner space ofthe discharge cover 34, toward the upper inner space 1 a of the casing1. The discharge cover 34 may be provided with a through hole 341,through which an oil feeder 6 may be inserted. The oil feeder 6 may becoupled to a sub bearing 52 of the rotational shaft 5, which will bediscussed hereinbelow, corresponding to a second bearing, and sunk inthe oil storage space 1 b of the casing 1.

A second bearing hole 325, through which the sub bearing 52 of therotational shaft 5 may be penetratingly coupled, may be formed in anaxial direction through a central portion of the disk 321 of the fixedscroll 32. A thrust bearing 326, which may support a lower end of thesub bearing 52 in the axial direction, may protrude from an innercircumferential surface of the second bearing hole 325.

The orbiting scroll 33 may include a disk 331 formed in an approximatelycircular shape, and the orbiting wrap 332 may be formed on a lowersurface of the disk 331 and be engaged with the fixed wrap 322 to formthe compression chambers S1. A rotational shaft coupling portion 333, inwhich an eccentric portion 53 of the rotational shaft 5, which will bediscussed hereinbelow, may be rotatably inserted, may be formed in theaxial direction through a central portion of the disk 331. An outercircumference of the rotational shaft coupling portion 333 may beconnected to the orbiting wrap 332 so as to form the compressionchambers S1 along with the fixed wrap 322 during compression.

The eccentric portion 53 of the rotational shaft 5, which will bediscussed hereinbelow, may be inserted into the rotational shaftcoupling portion 333, so as to overlap the orbiting wrap 332 or thefixed wrap 322 in a radial direction of the compressor. Accordingly, arepulsive force of a refrigerant may be applied to the fixed wrap 322and the orbiting wrap 332 upon compression, and a compression force as areaction force may be applied between the rotational shaft couplingportion 333 and the eccentric portion 53. In such a manner, when theeccentric portion 53 of the rotational shaft 5 penetrates through thedisk 331 of the orbiting scroll 33 and overlaps the orbiting wrap 332 inthe radial direction, the repulsive force and the compression force maybe applied to or at a same plane based on the disk, thereby beingattenuated by each other. This may result in preventing the orbitingscroll 33 from being inclined due to the applied compression force andrepulsive force.

The rotational shaft 5 may have an upper portion press-fitted into acenter of the rotor 22 and a lower portion coupled to the compressiondevice 3, so as to be supported in the radial direction. Accordingly,the rotational shaft 5 may transfer a rotational force of the motor 2 tothe orbiting scroll 33 of the compression device 3. The orbiting scroll33, which may be eccentrically coupled to the rotational shaft 5, maythus orbit with respect to the fixed scroll 32.

The main bearing 51, which may be inserted into the first bearing hole311 of the main frame 31 to be supported in the radial direction, may beformed at a lower portion of the rotational shaft 5, and the sub bearing52, which may be inserted into the second bearing hole 325 of the fixedscroll 32 to be supported in the radial direction, may be formed at alower side of the main bearing 51. The eccentric portion 53, which maybe coupled to the rotational shaft coupling portion 333 of the orbitingscroll 33 in an inserting manner, may be formed between the main bearing51 and the sub bearing 52. The main bearing 51 and the sub bearing 52may be coaxially formed to have a same axial center, and the eccentricportion 53 may be eccentric from the main bearing 51 or the sub bearing52 in the radial direction. The sub bearing 52 may also be formed to beeccentric from the main bearing 51.

The eccentric portion 53 may have an outer diameter which may be smallerthan an outer diameter of the main bearing 51 and greater than an outerdiameter of the sub bearing 52, which may be advantageous in view ofcoupling the rotational shaft 5 through the bearing holes 311, 325 andthe rotational shaft coupling portion 333. However, when the eccentricportion 53 is not integrally formed with the rotational shaft 5, butrather, is formed using a separate bearing, insertion of the rotationalshaft 5 for coupling may be enabled even though the outer diameter ofthe sub bearing 52 is not smaller than the outer diameter of theeccentric portion 53.

An oil passage 5 a, through which oil may be supplied to each bearingand the eccentric portion 53, may be formed within the rotational shaft5. As the compression device 3 is located lower than the motor 2, theoil passage 5 a may be formed in a recessing manner from a lower end ofthe rotational shaft 5 up to an approximately lower end or anintermediate height of the stator 21, or up to a height higher than anupper end of the main bearing 51.

The oil feeder 6 to pump up oil filled in the oil storage space 1 b maybe coupled to a lower end of the rotational shaft 5, namely, a lower endof the sub bearing 52. The oil feeder 6 may be provided with an oilsupply pipe 61, which may be inserted into the oil passage 5 a of therotational shaft 5 for coupling, and an oil sucking member 62, such as apropeller, may be inserted into the oil supply pipe 61 to suck up theoil. The oil supply pipe 61 may be inserted through the through hole 341of the discharge cover 34 so as to be sunk into the oil storage space 1b.

Unexplained reference numeral 35 denotes an Oldham ring, 351 denotes akey of the Oldham ring 35, 335 denotes a key groove of the orbitingscroll 33, and 551, 553, and 556 denote oil-feeding holes, respectively.

Operation of the scroll compressor according to this embodiment will bediscussed as follows.

That is, when power is applied to the motor 2 so as to generate arotational force, the rotational shaft 5 coupled to the rotor 22 of themotor 2 may be rotated. In response, the orbiting scroll 33 coupled tothe eccentric portion 53 of the rotational shaft 5 may continuously movewhile performing an orbiting motion, thereby forming between theorbiting wrap 332 and the fixed wrap 322 the plurality of compressionchambers S1, which may include a suction chamber, an intermediatepressure chamber, and a discharge chamber. The compression chambers S1may be continuously formed through several stages while their volumesare gradually decreased toward a central direction.

Accordingly, a refrigerant, which may be supplied from outside of thecasing 1 through the refrigerant suction pipe 15, may be introduceddirectly into the compression chambers S1. The refrigerant may becompressed while moving toward the discharge chamber of the compressionchambers S1 in response to the orbiting motion of the orbiting scroll33, and then, may be discharged from the discharge chamber into theinner space 1 a of the discharge cover 34 through the discharge opening324 of the fixed scroll 32.

The compressed refrigerant discharged into the inner space 1 a of thedischarge cover 34 may be then be discharged into the inner space 1 a ofthe casing 1 through the refrigerant passage PG, which may be formedalong the fixed scroll 32 and the main frame 31, thereby beingdischarged out of the casing 1 through the refrigerant discharge pipe16. This series of processes may be repeated.

With coupling the Oldham ring 35 between the main frame 31 and theorbiting scroll 33, the orbiting scroll 33 may perform an orbitingmotion with respect to the main frame 31 or the fixed scroll 32 whileits rotation is prevented. However, the Oldham ring 35 and the orbitingscroll 33, as illustrated in FIGS. 2 and 3 , may be coupled by virtue ofthe keys 351 and the key grooves 335. The keys 351 and the key grooves335 may be spaced apart from each other by a clearance gap δ1 of, forexample, about 20 to about 100 μm, such that the orbiting scroll 33 maysmoothly slide to perform the orbiting motion. The clearance gap δ1 mayallow the orbiting scroll 33 to generate a rotational moment or aninverse rotational moment during operation. This may result ingeneration of an interference section {circle around (4)} and gapsections {circle around (1)}, {circle around (2)}, {circle around (3)},{circle around (5)} and {circle around (6)} between the orbiting wrap332 and the fixed wrap 322.

The interference section and the gap sections may be generated when thefixed wrap 322 and the orbiting wrap 332 have irregularities, namely,when a wrap curve is irregular without any rule, unlike an involutecurve or an algebraic spiral curve, which is regular with apredetermined rule. FIG. 4 is a planar view of a fixed wrap and anorbiting wrap having an irregular wrap curve according to an embodiment.

The fixed wrap 322 and the orbiting wrap 332 illustrated in FIG. 4 havea shape for which a plurality of arcs with different radiuses and originpoints are connected, and an outermost curve has an approximately ovalshape having a major axis and a minor axis. The rotational shaftcoupling portion 333 may be formed at a central portion of the orbitingwrap 332 to overlap the orbiting wrap 332 in a radial direction. Aconcave portion 333 a may be formed on an outer circumferential surfaceof the rotational shaft coupling portion 333, and a protrusion 322 a maybe formed at an end of the fixed wrap 322 corresponding to the concaveportion 333 a.

The fixed wrap 322 and the orbiting wrap 332 having such irregular shapemay generate the interference section {circle around (4)} and the gapsections {circle around (1)}, {circle around (2)}, {circle around (3)},{circle around (5)} and {circle around (6)} therebetween due to anunnatural connection at portions where the arcs having the differentradiuses and origin points are connected. More specifically, referringto FIG. 4 , based on a line that connects a start point A, which is anouter end of the fixed wrap 322 or the orbiting wrap 332, and a center 0of each scroll, the interference section {circle around (4)} and the gapsections {circle around (1)}, {circle around (2)}, {circle around (3)},{circle around (5)} and {circle around (6)} may be formed at an area atwhich an end point of the fixed wrap 322 is located.

FIGS. 5 and 6 are graphs of a representative example of a gap sectionillustrating an orbiting radius displacement with respect to aninterference section and gap sections between the fixed wrap and theorbiting wrap forming A-path and B-path. FIG. 5 is a graph illustratinginterpretation of an orbiting radius displacement of a gap section withrespect to A-path of FIG. 4 . FIG. 6 is a graph illustratinginterpretation of an orbiting radius displacement in a gap section withrespect to B-path of FIG. 4 . In the graphs, ‘0’ indicates a statewithout any interference and gap, ‘+’ indicates a state withinterference, and ‘-’ indicates a state with a gap.

As illustrated in FIG. 5 , considering a first compression chamber(hereinafter, also referred to as “A-path”) formed on an inner surfaceof the fixed wrap 322, a gap, which may be about 12

long in maximum, may be generated in a vicinity of 200° based on a crankangle. The gap may narrow, and thus, the orbiting radius displacementmay become 0 (zero) in the vicinity of 320°. A state of the orbitingradius displacement of 0, which is a state without interference and gap,may be maintained for a predetermined section, and then, interference,which may be about 6

long in maximum may be generated in a section of about 540 to 600°.Then, a gap which may be about 8

long in maximum, may be generated in a section of about 600 to 660°.Afterwards, the orbiting radius displacement becomes 0 again up to about900°, and then, interference, which is about 6

long in maximum, may be generated up to about 980°. Then, a gap, whichis about 8

long in maximum, may be generated up to about 1000°, and thereafter, theorbiting radius displacement of 0 is maintained up to about 1260°, whichmay be a suction time point.

Also, referring to FIG. 6 , considering the second compression chamber(hereinafter, also referred to as “B-path”) formed on an inner surfaceof the orbiting wrap 332, interference, which may be about 18

long in maximum may be generated at a section of about 106° to 180°based on the crank angle, and then, a gap, which may be about 13.5

long in maximum, may be generated again at a section of about 180° to300°. After the state that the orbiting radius displacement is 0 (zero)may be maintained up to about 540°, interference which may be about 7

long in maximum, may be generated at a section of about 540 to 580°, andthen, a gap, which may be about 8.5

long in maximum may be generated again at a section of about 580 to660°. Afterwards, a state that the orbiting radius displacement is 0(zero) may be maintained up to about 903°. FIGS. 4 to 6 have notillustrated interference and gap less than 2

.

Therefore, an interference avoiding portion or a gap compensatingportion may be formed at positions at which the interference and gap ofA-path and B-path are generated, to offset the interference and the gapbetween the wraps, thereby preventing frictional loss or abrasion due tothe interference between the fixed wrap and the orbiting wrap, and alsopreventing in advance refrigerant leakage due to the gap. For reference,the interference avoiding portion may be defined as being formed toincrease a spacing between wraps to be greater than the orbiting radiuswhile a center of the fixed scroll and a center of the orbiting scrollare aligned with each other, and the gap compensating portion may bedefined as being formed to decrease the spacing between the wraps to besmaller than the orbiting radius while the center of the fixed scrolland the center of the orbiting scroll are aligned with each other.

FIG. 7 is a planar view of the B-path as a representative example forillustrating a structure for avoiding interference and gap between thefixed wrap and the orbiting wrap forming the A-path and the B-path. Asillustrated in FIG. 7 , a recess 301 to avoid interference may be formedat each section whether the interference is generated in the orbitingwrap 332 based on the crank angle (for example, a section in thevicinity of 106 to 180°, a section in the vicinity of 540 to 580°; FIG.7 merely illustrates the section in the vicinity of 106 to 180°). Aprotrusion 302 for compensating for a gap may be formed at each sectionwhere the gap is generated (for example, a section in the vicinity of180 to 300°, and a section in the vicinity of 580 to 660°). Accordingly,an orbiting radius r₁ at the section with the recess 301 may be greaterthan an original orbiting radius r₀, and an orbiting radius r₂ at thesection with the protrusion 302 is smaller than the original orbitingradius r₀.

In such a manner, interference may be avoided at the section at whichthe interference is generated between the fixed wrap and the orbitingwrap, and simultaneously, the gap may be compensated for at the sectionat which the gap is generated, thereby preventing frictional loss orabrasion between the wraps, and refrigerant leakage due to the spacedwraps.

A maximum depth of the recess 301 forming the interference avoidingportion and a maximum height of the protrusion 302 forming theinterference compensating portion may be the same as or more than atleast about 50% of a maximum interference height or a maximum gap heightof each section, such that an interference avoiding effect and a gapcompensation effect may be expected. In addition, the recess 301 and theprotrusion 302 may have a same sectional area in an axial direction ofeach wrap, such that a gap between the wraps maybe reduced.

Configurations and methods of the compressor according to embodimentsmay not be limitedly applied, but such embodiments may be configured bya selective combination of all or part of the embodiments so as toimplement many variations.

Embodiments disclosed herein provide a scroll compressor capable ofpreventing abrasion or refrigerant leakage between a fixed wrap and anorbiting wrap in a manner of preventing generation of interference or agap between the fixed wrap and the orbiting wrap.

Embodiments disclosed herein provide a scroll compressor including afixed scroll having a fixed wrap, and an orbiting scroll including anorbiting wrap engaged with the fixed wrap to form compression chambers.The fixed wrap and the orbiting wrap may have irregular wrap curves. Atleast one interference avoiding portion at which a spacing between thewraps is greater than an orbiting radius or at least one gapcompensating portion at which a spacing between the wraps is smallerthan the orbiting radius, in a state in which a center of the fixedscroll and a center of the orbiting scroll are aligned with each other,may be provided on a sidewall surface of the fixed wrap or the orbitingwrap.

The fixed wrap or the orbiting wrap may have a shape for which aplurality of arcs having different diameters and origin points areconnected together, and the interference avoiding portion or the gapcompensating portion may be located at each portion at which the arcshaving the different diameters and origin points are connected to eachother. The interference avoiding portion and the gap compensatingportion may be formed at one side area based on a line that connects astart point as an outer end of the fixed wrap or the orbiting wrap and acenter of each scroll.

The interference avoiding portion and the gap compensating portion maybe formed at an area at which an end point of the fixed wrap is locatedbased on the line. The interference avoiding portion may be formed as arecess on the sidewall surface of the fixed wrap or the orbiting wrap,and the gap compensating portion may be formed as a protrusion on thesidewall surface of the fixed wrap or the orbiting wrap.

The recess or the protrusion may be formed to be more than about 50% ofa highest interference height or a highest gap height of each section.The recess or the protrusion may have a same sectional area along aheightwise direction of the wrap.

The orbiting scroll may be coupled in a manner that an eccentric portionof a rotational shaft for orbiting the orbiting scroll overlaps theorbiting wrap in a radial direction.

Embodiments disclosed herein further provide a scroll compressor thatmay include a casing, a motor unit or motor that is disposed within aninner space of the casing, a frame that is fixedly coupled to the innerspace of the casing, a fixed scroll that is fixedly coupled to the frameand has a fixed wrap, and an orbiting scroll that is located between theframe and the fixed scroll and has an orbiting wrap engaged with thefixed wrap to form compression chambers, the orbiting scroll performingan orbiting motion, an Oldham ring that is slidably coupled with theorbiting scroll with a clearance gap therebetween and configured toprevent rotation of the orbiting scroll, and a rotational shaft that iscoupled to the orbiting scroll and has an eccentric portioneccentrically coupled to the orbiting scroll. The eccentric portion mayoverlap the orbiting wrap in a radial direction. The fixed wrap or theorbiting wrap may have at least one section where or at which anorbiting radius is smaller or greater than a preset or predeterminedorbiting radius according to a turning direction of each wrap.

A recess to avoid interference may be provided at a section of anorbiting scroll or a fixed scroll, at which the interference isgenerated, and a protrusion to compensate for a gap may be provided at asection of the orbiting scroll or the fixed scroll, at which the gap isgenerated. This may result in avoiding interference and compensating forthe gap between the wraps, thereby preventing frictional loss orabrasion between the wraps and refrigerant leakage due to the gapbetween the wrap.

Further scope of applicability of embodiments will become more apparentfrom the detailed description given herein. However, it should beunderstood that the detailed description and specific examples, whileindicating embodiments, are given by way of illustration only, asvarious changes and modifications within the spirit and scope willbecome apparent to those skilled in the art from the detaileddescription.

As features may be embodied in several forms without departing from thecharacteristics thereof, it should also be understood that theabove-described embodiments are not limited by any of the details ofthis description, unless otherwise specified, but rather should beconstrued broadly within its scope as defined in the appended claims,and therefore all changes and modifications that fall within the metesand bounds of the claims, or equivalents of such metes and bounds aretherefore intended to be embraced by the appended claims.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A compressor comprising: a case; a driving unitfixed to the inside of the case to rotate the rotating shaft; anorbiting scroll including an orbiting end plate rotatably supporting therotating shaft, and an orbiting wrap extending from one surface of theorbiting end plate toward an outer circumferential surface of therein; afixed scroll including a fixed end plate fixed to the case, and a fixedwrap extending to compress the refrigerant in engagement with theorbiting wrap on the fixed end plate portion; and wherein the fixed wrapcomprises a specific area provided with a thickness greater than athickness of an area adjacent to the specific area.
 2. The compressoraccording to claim 1, wherein the specific area is disposed in an areaextending 360 degrees or more from an inner end of the fixed wrap. 3.The compressor according to claim 1, wherein the thickness of thespecific r area is formed to become thicker and then thinner along theextending direction from an inside to an outside of the fixed wrap. 4.The compressor according to claim 1, wherein an outer surface and aninner surface of the specific area are formed to have different radiusof curvature.
 5. The compressor according to claim 1, wherein athickness of an area of the orbiting wrap facing the specific area isformed to correspond to a thickness of an adjacent area of the orbitingwrap.
 6. The compressor according to claim 1, wherein an inner end ofthe fixed wrap is formed thicker than the area adjacent to the inner endof the fixed wrap.
 7. The compressor according to claim 1, wherein thethickness of an inner end of the fixed wrap is formed to be thicker thanthe thickness of an outer end of the fixed wrap.
 8. The compressoraccording to claim 1, wherein a center (O1′) of an inner curve of aninner end of the fixed wrap and a center (O1) of the fixed end plate areformed to be spaced apart each other.
 9. The compressor according toclaim 1, wherein an inner end of the orbiting wrap is provided thickerthan the area adjacent to the inner end of the orbiting wrap.
 10. Thecompressor according to claim 1, wherein an inner end of the orbitingwrap is provided to be thicker than an outer end of the orbiting wrap.11. A compressor comprising: a case; a driving unit fixed to the insideof the case to rotate the rotating shaft; an orbiting scroll includingan orbiting end plate rotatably supporting the rotating shaft, and anorbiting wrap extending from one surface of the orbiting end platetoward an outer circumferential surface of therein; a fixed scrollincluding a fixed end plate fixed to the case, and a fixed wrapextending to compress the refrigerant in engagement with the orbitingwrap on the fixed end plate portion; and wherein the fixed wrap isprovided with an area (A) that is thickened and then thinned whileextending from a center of the fixed end plate to an outercircumferential surface of the fixed end plate.